The present invention relates generally to plastic tube bundle clamps. More particularly, the invention relates to a unitary clamp comprising two cooperating jaws which interlock to form a substantially circular, gap-less and leak-proof mounting orifice This invention is believed best classified in U.S. Utility Class 24, subclass 16 R.
In recent years plastic tubing or hose clamps have become increasingly popular. Such devices are typically integrally molded from plastic, and they include a circular band portion adapted to encircle the cables or other items being fastened, which terminates in integral, cooperating jaws which may be snap-fitted together. Typical jaws comprise one or more cooperating elements, which are provided with suitable teeth to inter-fit with one another when the jaws are compressed together As the jaws are compressed, the band portion of the clamp is vigorously tightened about the tubes, wires, conduits or the like to be restrained.
Representative of such prior art clamp elements is U.S. Pat. No. 3,605,200 issued to Vallinotto et al. on Sept. 20, 1971. The '200 device comprises a generally U-shaped clamp terminating at each end in an open jaw comprising a toothed edge and an opposing smooth edge. When properly sealed, the toothed edges interlock and the smooth jaw portions remain slidably coupled to provide a smooth clamping surface. Similarly, U.S. Pat. No. 4,372,011 issued to Aranyos on Feb. 8, 1983 comprises a unitary ring having a plurality of interlocking toothed jaw members and a sealing rib formation. The Aranyos device includes an internally defined shoulder adapted to limit travel of the jaw members relative to one another to prevent over-tightening. U.S. Pat. No. 3,925,851 (this device is illustrated in FIG. 17 of the accompanying drawings) issued to Bevins on December 16, 1975 comprises a similar hose clamp the internal ring of which comprises a conical surface terminating in a definitive ridge. When the clamp is closed, the ridge projects inwardly to more firmly contact the outer surface of the hose and prevent loosening or leakage. A pair of indentions or shoulders are provided to limit travel of the jaw members relative to one another and prevent over tightening.
U.S. Pat. No. 4,128,918 issued to Wenk, discloses an adjustable snap-on clamp having a band and a pair of cooperating jaws equipped with teeth which interlock with one another. A special cantilevered tongue construction is employed to aid the efficiency of jaw function. Importantly, because of the tapered lower jaw element, the device internally approximates a circular cross sectional profile to prevent damage to bundled tubes, wires or the like when the jaws are forcibly compressed. Other prior art clamps of lesser relevance to my invention include U.S. Pat. Nos. 4,183,120; 3,229,998; and, 673,382.
One problem associated with known prior art tubing clamps is that the jaws may inadvertently become opened when subjected to certain stresses. All plastic tubing clamps known to me can be manually forced open when the jaws are transversely moved relative to one another. However, such transverse jaw displacements may occur in active installations, when the bundle ties are employed with parts which are subject to vibrations or movement which might induce shearing stresses. For example, it is well recognized that when used with fuel lines adjacent to internal combustion motors, vibrational and bending forces may tend to transversely displace the clamp jaws In extreme situations the jaws may become transversely displaced from one another enough to totally separate and release the clamp. My clamp is designed to prevent such opening.
Another problem is that clamps tend to "leak." In other words, when the jaws are forced together, the inner substantially circular periphery of the band, which is in close contact with the elements restrained by the clamp, may have internal gaps or surface discontinuities. Gap-like discontinuities may form between the leading edge of the inner bottom jaw element, and the opposite side of the band at which said leading edge terminates. Wires or tubes lodged in this area can become damaged when the clamp is thereafter tightened.
It is thus desirable to present, to the fullest extent possible, a continuous, gapless inner band periphery which is free from irregularities or surface discontinuities. The band should have no 37 gaps" or discontinuities of the type which extend across its entire width. The aforementioned Wenk reference attempts to accomplish this by providing a lower jaw member of tapering construction. The thin leading element of the lower jaw essentially tangentially contacts the underside of the opposite jaw, so that its inner periphery approximates the continuous smooth geometry of a circle. Nevertheless, with this clamp and with others, the small discontinuity formed can be disadvantageous. And, in many prior art designs, the width of the unwanted gap is a function of jaw compression. The less the jaws are compressed, the wider the exposed gap is.
Gaps of this nature encourage the destruction of that bundle or tube element compressibly wedged into the gap region. The undesirable resultant "leak" characteristic of the bundling clamp is thus enhanced. I have found it to be extremely desirable to provide some form of physical contact within the inner periphery of the clamp against the circumference of the bundled wires or tubes, even when the clamp is only partially compressed. In other words, it is extremely desirable that the cable clamp provide at least a portion of plastic surface to form a continuous inner plastic contact area of substantially circular dimensions so that no wire, or tube will destructively be forced against any internal boundary discontinuity or gap.